This product you see here is called the XCM Magic Night Glow faceplate. It latches onto the front side of slim model PSPs only and comes in pearl, yellow, blue (pictured), green, pink, and red. Each faceplate glows a different color than its original scheme. For example: the blue one pictured above will glow greenish (also pictured). So far there's no price set yet, but you can find a place to pre-order it over at XCM's website.
Now, just think of all the practical uses your PSP will now have; it's not only a game machine and a music player, but also a nightlight and a rave party glow toy! Sweet.